Here are the details of this operation: Diagnosis interface boot
(rescue) Date 2016-08-11 19:55:22, elyess H made Diagnosis interface
boot (rescue): Here are the details of the operation performed: The
server gets stuck during the boot phase, with the message: (error:
unknowk filesystem) A restart on the standard OVH kernel ('netboot')
does not correct the situation.

Actions: Rebooting the server to "rescue" mode (Linux)

result: Boot OK. Rescue mode accessible.

recommendations: Configuration / error to be corrected by the customer

So the PROBLEM: I lost my filesystem, and I cannot start, and I cannot mount the disk.
I have RAID-1 in the dedicated server, but I cannot mount /dev/md1.

How can I restore the file system? How can I mount the disk? How can I start the system? I think if I solve the filesystem, i will can start the system.

This question appears to be off-topic. The users who voted to close gave this specific reason:

"Questions should demonstrate reasonable business information technology management practices. Questions that relate to unsupported hardware or software platforms or unmaintained environments may not be suitable for Server Fault - see the help center." – Chopper3, Basil, mdpc

It's important that you understand that what you've done is staggeringly unprofessional and you've then come a place specifically for professionals to ask for hep - imagine if you'd walked into a airline pilot lounge and said "I appear to have sawn my plane's wings off - halp!"
– Chopper3Aug 12 '16 at 12:05

5

I'm voting to close this question because the OP needs tech support and not Q&A.
– IainAug 12 '16 at 13:28

Raid-0 is stripped raid - you're using all capacity of all of your drives and data are saved across all disks, but you have no redundancy for case of failing device.

And this is what happened to your server. One of your disks failed. It is common thing in server environment. But because you have only RAID-0 configuration, you're screw and all of your data are lost.

Now it depends on value of data saved on your server. You can try to talk with OVH to power off your server, take those drives out and send it to some company specialized to rescue data from failed drives. It is expensive service and you have no guarantee they will restore 100% of your data. It will definitely take days or weeks to restore it and your server will be offline for this time.